Recently, crosslinked polymer microparticles have been watched with keen interest in paint industries as a prominent additive for various paints, as, for example, rheological regulator, filler, modifier or the like in aqueous coating compositions, high solid paints, powder coating compositions and the like. However, heretofore proposed microparticles are only of crosslinked polymer having no functional groups or at most of crosslinked polymer bearing carboxyl, hydroxyl or amino groups. Introduction of such functional groups to the crosslinked polymer is believed to be beneficial in obtaining an improved curability of a coating composition compounded with an aminoplast resin or polyisocyanate compound, or improved dispersibility of the polymer microparticles per se or pigment particles in a coating composition. On the other hand, there is a class of functional groups having relatively higher cohesive energy of atomic groups (Burn et al., J. Chim. Phys. 16, 323 (1955)) e.g. urea, urethane, amide groups and the like. However, a polymerizable monomer bearing such group is in general of high crystallinity and is hardly soluble in other copolymerizable monomers or solvents, and thus considerable difficulties are encountered in the actual handling of such monomer. Moreover, even if resinous particles bearing such functional groups be provided, it would be most probable that the particles are easily associated or agglomerated together due to the presence of said groups with higher cohesive energy. Such properties are undesirable for the polymer microparticles to be compounded with a coating composition, and in fact, no such particles have been prepared and used in the related technical fields. In the paint industry, there is a firm demand for obtaining a high solid coating composition having improved application characteristics and storage stability, capable of providing a coating with far improved coating appearance, and for developing a new type polymer microparticles to be compounded with such composition. It is, therefore, an object of the invention to provide novel crosslinked polymer microparticles which can be used in various paints including aqueous coating compositions, high solid coating compositions, powder coating compositions and the like, to improve film-forming properties of said paints. An additional object of the invention is to provide a high solid coating composition containing such polymer microparticles, which is excellent in application characteristics and storage stability, and is capable of providing a coating with far improved appearance and especially gloss and sharpness.